String Similarity Algorithms (Matching Percentage)

Hi. Nice work on this. But how do you get the "string cleanup" activity working? I have version 1.0.0 and all I get are these errors:

RemoteException wrapping System.NullReferenceException: Object reference not set to an instance of an object. 

   at InternalLabs.StringAlgorithms.Activities.StringCleanup.d__62.MoveNext()

I have a simple assign: input_string = "Hello world"

Then I have this activity.

Then I save the output as a string as well. But it seems to crash on the activity itself.

It doesn't matter if I have any options selected or not.

What's happening?

Thanks.